Arsenal head coach Jonas Eidevall has resigned.
The north London club sit sixth in the Women's Super League (WSL) after winning just one of their opening four games of the 2024-25 season.
Assistant coach Renee Slegers will take charge on an interim basis.
"We thank Jonas for his commitment to the club and achievements here since joining us in 2021," sporting director Edu said.
"We have great respect for the dedication and commitment he showed to our women’s first team and recognise the role he has played in the growth and development of Arsenal Women."
Eidevall signed a new three-year contract with the club last October after consecutive top-three finishes in the WSL, while also winning the Women's League Cup in the past two seasons.
Arsenal failed to win any of their last three games under the Swede, drawing one and losing two.
They suffered a heavy 5-2 defeat at Bayern Munich in the Champions League on Wednesday, before slipping to a 2-1 loss at home to Chelsea three days later.
"Our focus will now turn to the process of appointing a new head coach, and in the meantime, supporting Renee [Slegers], as she takes interim charge of the team starting with two important fixtures this week," Edu added.
Slegers' first match comes on Wednesday when Norwegian club Valerenga visit in the Champions League.
Arsenal then make the short trip to London rivals West Ham, who are 11th and yet to win in the WSL this season.
Slegers joined Arsenal as assistant in September last year having worked with Eidevall previously in Sweden.
The pair were at Rosengard before Slegers succeeded Eidevall at the club in June 2021, going on to lead them to back-to-back titles.
"I was shocked by the news and was very sad," Slegers said.
"He has been a good leader for the staff. I worked with him before in Sweden. We worked well together and I'm sad it got to this point."
Asked if she wanted the job full-time at Arsenal, Slegers added: "Right now I just focus on these next two games ahead of us.
"The future I am not so concerned about."
Director of women’s football Clare Wheatley said: "Jonas has brought us back-to-back trophies in the last two seasons, together with many memorable moments on the pitch.
"We have full confidence in Renee to take responsibility for the team in the interim period."
Eidevall arrived at Arsenal from Rosengard after leading the Swedish club to the quarter-finals of the Women's Champions League in 2020-21.
The 41-year-old, who also had a brief spell as Henrik Larsson's assistant at Helsingsborgs, won three league titles during two spells at Rosengard.
Eidevall utilised his knowledge of the Swedish league to bolster his squad during his first summer with the Gunners, signing forward Stina Blackstenius and midfielder Frida Maanum.
Arsenal finished second, one point shy of champions Chelsea, in Eidevall's maiden campaign - their highest finish since winning the WSL in 2018-19. They also reached the semi-finals of the FA Cup and quarter-finals in the Champions League and League Cup.
Silverware arrived in Eidevall's second season at the helm, beating Chelsea 3-1 in the League Cup final.
The signing of England forward Alessia Russo last summer offered hope that Arsenal could bridge the gap to WSL champions Chelsea.
They managed to retain the League Cup but finished third in the WSL and exited the Champions League in the first qualifying round.
The departure of striker Vivianne Miedema, who scored 125 goals and provided 50 assists in 172 appearances, over the summer was regarded as a big blow, although Eidevall did sign Spain World Cup winner Mariona Caldentey as a replacement.
Eidevall departs Arsenal with a 70% win ratio, having taken charge of 70 matches - winning 49, drawing 10 and losing 11.
Only Joe Montemurro (75.71%) and Laura Harvey (71.43%) had better win records at the club, from managers to have overseen at least 10 games.
Arsenal captain Kim Little said the players found out the news of Eidevall's departure on Tuesday morning.
"We were made aware in our team meeting, before we went to train," she said.
"[It's sad]. We have a huge amount of respect for him as players. It is obviously a big change but we need to move forward now.
“The strength of what Jonas has left is that the foundations are here. The club has everything in place to succeed."
Emma Sanders, BBC Sport women's football news reporter
Pressure has been building on Eidevall but the feeling from Arsenal last week was that they backed him, and the result against Chelsea was unlikely to sway their thinking - at least not immediately.
But Eidevall himself will have seen the reaction from the Arsenal fanbase and the media, with their poor start to the season reflected in results.
P45 signs - calling for his sacking - could be seen in some parts of Emirates Stadium during Saturday's 2-1 defeat, while a picture of a wall displaying the words 'Jonas Out' in graffiti was later shared on social media.
Eidevall did not defend himself in the post-match media conference, instead pointing to the resilience shown by his players and pleading with supporters to keep belief.
It felt only a matter of time before he would need to step away, or the club would have to make that decision for him.
Eidevall returned to the training ground on Monday and informed the club of his intention to step down. He felt he was not the right person to take the club forward.
He has made changes during his time at the club, improving professionalism, but ultimately failed to meet the raised expectations he had set - and that has proved costly.
There are a few coaches available who would make strong candidates, none more so than former Manchester United manager Casey Stoney - who was invited by Arsenal to watch their defeat by Chelsea at the Emirates. However, she is not currently being considered.
Elsewhere, former Arsenal striker Kelly Smith is already working at the club and may throw her name in the hat, while ex-Netherlands manager Mark Parsons is also looking for a job.